Timothy,
It isn't a situation I come across often but I would do what you are already doing in advising you can accept either clearance. It really is traffic situation dependant and sometimes one works better than the other. Likewise the level issue, we try to keep you where possible at the level you are already maintaining , however if you consider that an alternative level may help the ATCO out advise you can accept an alternative if required.
"Yeah whatever" is a phrase we often bandy around in jest , flexibility is great but where ever possible we like to try to give you what you require.